1. Technical Field
The present invention relates to a windscreen wiper device, particularly for automobiles, comprising an elastic, elongated carrier element, as well as an elongated wiper blade of a flexible material, which can be placed in abutment with a windscreen to be wiped, which wiper blade is of the flat blade type and includes at least one groove, in which groove a longitudinal strip of the carrier element is disposed, wherein the windscreen wiper device comprises a mounting head for transferring a reciprocal movement to an oscillating arm, wherein the windscreen wiper device further comprises a connecting device for detachably connecting the wiper blade to the oscillating arm near one end thereof around a pivot axis.
The invention also refers to a wiper blade to be used in such a windscreen wiper device.
2. Related Art
Such a windscreen wiper device and such a wiper blade are generally known. This prior art wiper blade is designed as a so-called “flat blade” or “yokeless blade”, wherein no use is made of several yokes pivotally connected to each other, but wherein the wiper blade is biassed by the carrier element, as a result of which it exhibits a specific curvature. In practice the wiper blade often comprises a spoiler at a side thereof facing away from the windscreen to be wiped. The spoiler is also called an “air deflector”.
The object of the invention is to provide an improved windscreen wiper device.
In order to accomplish that objective, a windscreen wiper device of the type referred to in the introduction is characterized according to the invention in that the connecting device has a substantially U-shaped cross-section, wherein legs of the U-shaped cross-section are connected to the flexible material of the wiper blade on opposite sides thereof, wherein the legs are provided with two pairs of opposite protrusions near the outer ends of the connecting device, and wherein the protrusions extend laterally inwardly for exerting only a transverse force on the flexible material of the wiper blade, thereby locally squeezing the flexible material onto the longitudinal strip, in order to block any lateral movement of the longitudinal strip at the location of the interconnection of the connecting device and the wiper blade. In use, during each oscillatory movement of the oscillatory arm, the wiper blade at the location outside the connection device would normally suffer from the so-called “fishtailing phenomenon”, wherein the wiper blade on opposite sides of the connecting device vibrates in an uncontrollable manner parallel to a windscreen to be wiped. Obviously, this “fishtailing phenomenon” results in deteriorated wiping properties, with all negative consequences involved, particularly at high speeds. According to the invention the protrusions extend laterally inwardly only from a vertical part of each leg of the U-shaped cross-section for exerting only a transverse force on the flexible material of the wiper blade, thereby allowing the longitudinal strip to exhibit a curvature at the location of the interconnection of the connecting device and the wiper blade. Experimental results have shown that the “fishtailing phenomenon” is avoided at least to a large extend, so that the wiping properties are improved. Preferably, the ratio (L′/L) between the width L′ of the flexible material at the location of the protrusions and the width L of the flexible material at a location outside the protrusions (but inside the connecting device) varies between 30% and 1%. Preferably, the protrusions have a round cross-section.
It is noted that the present invention is not restricted to the use of only one longitudinal strip forming the elastic carrier element that is particularly located in a central longitudinal groove of the wiper blade. Instead, the carrier element may also comprise two longitudinal strips, wherein the strips are disposed in opposite longitudinal grooves of the wiper blade. Further, the present invention is not restricted to automobiles, but also refers to other fast vehicles, such as trains and the like.
In a preferred embodiment of a windscreen wiper device in accordance with the invention the legs of the U-shaped cross-section are movable from an open position, wherein the wiper blade including the longitudinal strip can be placed inside the connecting device at the location of their interconnection, to a closed position, and wherein the legs are clamped around the flexible material of the wiper blade. With the use of a special tool, the legs are particularly pushed against a spring force (as a result of the elasticity of the material from which the connecting device is made) from the closed position into the open position, wherein the legs are allowed to automatically spring back from the open position into the closed position.
In another preferred embodiment of a windscreen wiper device according to the invention in the closed position the wiper blade and the longitudinal strip are mutually fixated by the legs at the location of the interconnection of the connecting device and the wiper blade, wherein in the closed position the wiper blade is allowed to move in longitudinal direction relative to the longitudinal strip outside the location of the interconnection of the connecting device and the wiper blade. In other words, the wiper blade and the longitudinal strip are not allowed to mutually move under the connecting device, but in all other areas along the wiper blade a slight movement thereof is made possible in order to allow the wiper blade to follow any curvature of the windscreen to be wiped. In the closed position the legs are particularly slightly deforming (the rubber of) the wiper blade at the location of the interconnection of the connecting device and the wiper blade.
In another preferred embodiment of a windscreen wiper device in accordance with the invention the connecting device is detachably connected to oscillating arm with the interposition of a joint part, wherein the joint part is detachably connected to the connecting device by engaging protrusions of the connecting device, at the location of the pivot axis, in recesses provided in the joint part. This is preferably realized through a snapping or clipping operation.
In another preferred embodiment of a windscreen wiper device according to the invention the joint part has an at least substantially U-shaped cross-section at the location of its connection to the connecting device, wherein the joint part is provided with the recesses provided coaxially with the pivot axis. In particular, the protrusions extend outwards on either side of the connecting device and are preferably cylindrical in shape. In the alternative, the protrusions are spherical or frusto-conical in shape. the protrusions that function as bearing surfaces are thus paced far apart, so that forces exerted thereon will be relatively low. In yet another preferred variant the joint part is provided with co-axial through holes in legs of the U-shaped cross-section thereof, wherein a pivot pin is inserted in the through holes. Accordingly, the wiper blade may then be connected to the oscillating arm on the basis of a so-called “sidelock system”. The oscillating arm is provided with a joint pin or a pivot pin to be inserted in the co-axial through holes. The pivot pin protrudes in a direction towards the wiper blade and has a pivot axis extending in a direction of the oscillating movement of the oscillating arm.
In another preferred embodiment of a windscreen wiper device in accordance with the invention the joint part comprises at least one resilient tongue engaging in a correspondingly shaped hole provided in a base of a U-shaped cross-section of the oscillating arm, and wherein the resilient tongue is rotatable along a hinge axis between an outward position retaining the wiper blade onto the oscillating arm and an inward position releasing the wiper blade from the oscillating arm. Accordingly, the wiper blade may then be connected to the oscillating arm on the basis of a so-called “toplock system” on the basis of a bayonet connection. In order to connect the wiper blade onto the oscillating arm, the resilient tongue is initially pushed in against a spring force—as if it were a push button—and then allowed to spring back into the hole provided in the oscillating arm, thus snapping, that is clipping the resilient tongue into the hole. By subsequently pushing in again the resilient tongue against the spring force, the wiper blade may be released from the oscillating arm.
A windscreen wiper device according to the invention comprises a mounting head fixed for rotation to a shaft, wherein the shaft is rotatable alternately in a clockwise and in a counter-clockwise sense carrying the mounting head into rotation. The oscillating arm is connected to the mounting head fixed for rotation to the shaft driven by a small motor.
In use, the shaft rotates alternately in a clockwise and in a counter-clockwise sense carrying the mounting head into rotation also, which in turn draws the oscillating arm into rotation and by means of the connecting device moves the wiper blade. Further, a windscreen wiper device in accordance with the invention comprises a connecting piece positioned on both ends of the wiper blade and connected to an end of the longitudinal strip.
The present invention also relates to a wiper blade manufactured as a single (separate) constructional element of a flexible material, which can be placed in abutment with a windscreen to be wiped, which wiper blade is of the flat blade type and includes at least one groove in which groove a longitudinal strip is disposed, the wiper blade comprising a connecting device detachably connected thereto, characterized by the connecting device having a substantially U-shaped cross-section, wherein legs of the U-shaped cross-section are connected to the flexible material of the wiper blade on opposite sides thereof, wherein the legs are provided with two pairs of opposite protrusions near the outer ends of the connecting device, and wherein the protrusions extend laterally inwardly for exerting only a transverse force on the flexible material of the wiper blade, thereby locally squeezing the flexible material onto the longitudinal strip, in order to block any lateral movement of the longitudinal strip at the location of the interconnection of the connecting device and the wiper blade.
It is noted that the connecting device is not necessarily made in one piece, but it can also be composed of an assembly of parts.